Apparatus employed in the formation of wells.



E. R. GNADE.

' APPARATUS EMPLOYED IN THE FdRMAHON OF WELLS.

APPLICATION FILED JULY 24, 1915.

I I I I I I I I I I l I 1 l I I I |v I I I 1 I I l l I 1 WITNESSES I I myzmwm M Mi,

barren srans PATENT OFFICE EDWARD R. GNADE, OF OIL CITY, PENNSYLVANIA, ASSIGNOE '10 OIL VI ELL SUPPLY COMPANY, OF PITTSBURGH. PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

APPARATUS EMPLOYED IN THE'POBIIIATION OF WELLS.

Specification of Letters-Patent.

Patented Jan. 8, 19118;

Application filed J u1y 24, 1915. Serial Ito-41,674.

ToaZZ whom it' mag concern Be it known that I, EDWARD R. GNADE, a citizen of'the United States, residing at Oil Gity, in the county of Venango and State of Pennsylvanim have invented certain new andl useful Improvements in Apparatus Employed in the Formation of lVells, of which thefollowing is a specification.

This invention relates to improvements in appliances used in connection with the formation and completion of deep wells, such for instance, as oil, gas, or Artesian wells, relatingmore particularly to the means employedk at the lower end of the casing or drive string for shaping thewell and for holding the lower end of the casing in position.

l/Vell casing and drive pipe strings are formed by a plurality of pipe sections connected'together endto end by suitable coupling connections which have the effect of producing annular projecting portions at the joints, thus increasing the diameter of the casing at these points. As the drilling tool generally is of acharacter which may not; provide an opening of a sizesuificient to pass these-portions of increased diameter, it has been the general practiceto employ what is knownin the art as a shoe, this' being in the form ofa member secured to the lower end ofthe casing or of the drive pipe and which; has its forward end of a diameter sufiicient toprovide clearance for these projecting. portions of'the casing, the shoe having a cutting edge which facilitates the ready shaving ofi ofthe sides of the hole where there are slight projections and which projections would interfere with the lowering of the pipe. Another function performed by these shoes is that provided when a string of pipe has been lowered to the required depth. At this time, it is customary, through the use ofdrive heads and weights on the top ofthe string of pipe, to drive the pipe and force the bottom of the string into the clay, or such other formation as may be found present and desirable to form the seat for the string, the string being set by such drive action. This function is provided by such shoes which act to prevent the pipe from collapsingwvlien being driven.

These shoes were generally secured in position on the lower section of the casing bya threading action, but it was found thatthe jarring and other strains to which the easing was subjected tended to loosen the threaded connection, with the result that the shoe dropped off and practically formed an obstruction through the inability to remove it, especially where the well had reached a great depth.

Attempts were made to remedy this condition, first, by providing such connection by additionally shrinking the shoe on the section, then by a riveting action, and finally by combining these methods, this being the present practice, viz., threading, shrinking and riveting the shoe in position. Obviously, this is an expensive ope-ration. Under service conditions, however, this construction is found unsatisfactory, since even this multiplicity of securing means has been found insufficient to prevent detachment of the shoe under drive operations incident to the placing of the casing in position, especially where the casing is of great length.

As heretofore pointed out, loss of the shoe will tend to plug the well, and the shoe is of, a character which cannot be readily fished out. Another objection in this respect is the fact that this multiplicity of securing means acts upon the end of the lower casing section in a manner which renders the section practically useless whenlossof the shoe occurs, excepting possibly by removing the affected portion of the section.

The present, invention aims to overcome these objections and at the same time provide certain additional advantages, among which is the fact that the drive pressures are communicated to the cutting edge direct and not through a joint or coupling action.

These results are obtained by forming the cutting edge directly upon the lower casing section, thus eliminating all liability of loss of a small section, producing a construction which is of suficient length to enable it to be readily fished out in case the joint between the lower section and that immediately above it is broken, leaving the lower casing section as a separate element, the fishing operation, in such case, being similar-to that employed for the removal of, an 0rdinary casing section.

To these and other ends, the nature of which will be readily understood as the invention is hereinafter disclosed, said invention consists in the improved construction and the method of producing the same here- 5 inafter' fully described, illustrated in the accompanying drawing, and more particularly pointed out in the appended claims.

In the drawing, in which similar reference characters indicate similar parts in each of the views,

Figure 1 is a side elevation of a portion of a string of casings or pipes embodying my invention;

Fig. 2 is a fragmentary sectional view of the lower end of a section.

Casing sections in general use are approximately twenty feet in length and have a diameter varying according to the size of the well, ranging from two to sixteen inches in diameter. Similarly, pipe sections which operate in driving the well and generally known in the trade as the drive pipe have similar lengths with diameters ranging from two to twenty inches. Since the present invention is applicable for use either in connection with drive pipe or casings, and is intended for use in either relation, an explanation relative to the construction of a drive pipe section will be sufficient. For example, the construction of a six-inch drive pipe is given.

Standard specifications of a six-inch drive pipe section are substantially as follows external diameter 6.625; internal diameter 6.065 outside diameter of coupling 7.473 length of pipe feet. The diameter of the hole or well must be such as to permit of the free passage of the coupling.

To produce the section of the present invention, I flare the lower end of the section by suitable means, the flare extending for a distance approximately two inches in length from the lower end, the flare being such as to gradually increase the thickness of the section toward its free end within this distance. The internal diameter of the lower end of the six-inch pipe referred to is increased to approximately 6.6875, while the outside diameter at the ame end is increased to approximately 7.6875, thus gradually increasing the thickness of the pipe from the normal wall thickness of .280 to a thickness of substantially one inch. The cutting edge is formed by beveling the lower edge inwardly at an angle of approximately thus placing the cutting edge at the extreme periphery of the point of largest diameter of the section, a diameter in excess of the outside diameter of the coupling. As inclicated, this illustration is simply an example as showing approximate variations which may be employed, it being understood, of course, that these specific dimensions are variable, and are intended to be approximate 65 only.

As shown more particularly in Fig. 2, this arrangement, through the gradual increase in thickness of the pipe wall toward the cutting edge, reduces the liability of the collapsing action at such lower end, and, in addition, provides an efficient cutting structure. As this flare or. expanded portion is formed as an integral part with the pipe section, it will be readily understood'th'at the section can be fished out as easily as the ordinary pipe section.

This flare of theend of the section may be provided in various well known ways which will produce this gradual increase in thickness of the pipe wall toward the cutting edge, the cost of forming the structure not being materially increased over the cost of producing the prior composite structure of pipe section and shoe, especially where the connection between these elements includes the threading, shrinking and riveting action; In addition, the elimination of any possibility of plugging the hole or well is of positive advantage.

In the drawing, the lowermost pipe section of a string is indicatedat 5, the adjacent section at 6, and the coupling at 7. The flare or expanded portion of section 5 is indicated at 8, and the cutting edge at 9, this structure being located only on the lowermost section.

As will be seen in Fig.2, the flare extends generally in the direction of length of the pipe section, while the cutting edge is formed by beveling the free end of the flared portion inwardly.

What I claim is 1. In apparatus adapted for use in the formation of wells, a string of pipe sections each having a length suflicient to permit its being fished out of the well individually, a separable external coupling member for connecting the lowermost pipe section to an adjacent section, said lowermost pipe section of the string having its free end flared outwardly in the direction of length of the section to an external diameter greater than the external diameter of the coupling, the wall thickness of the flared portion gradually increasing toward the free end of the flare.

2. In apparatus adapted for use in the formation of wells, a string of pipe sections each having a length suflicient to permit its being fished out of the well individually, a separable external coupling member for con- 12o necting the lowermost pipe section to an ad- 7 jacent section, said lowermost pipe section of the string having its free end flared outwardly in the direction of length of the section to an external diameter greater than the external diameter of the coupling.

3. In apparatus adapted for use in the formation of wells, a string of pipe sections each having a length sufficient topermit its being fished out of the well individually, a

separable external coupling member for connecting the lowermost pipe section to an adsaid of the string having its free end flared outwardly in the direction of length of the section to an external diameter greater than the external diameter of the coupling, the wall thickness of the flared portion gradually inj acent section,

Copies of this paten creasing toward and having an lowermost pipe section In testimony in presence of tw Witnesses 1; may be obtained for five cents each, by addressing Washington, D. G.

the free end of the flare inwardly beveled face.

whereof I aflix my signature 0 witnesses.

EDWARD R. GNADE.

E. E. Gnnvn, F. L. ENGLISH.

the Commissioner of Patents, 

